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1.
2.
The condensation reaction between α-keto-β-aroyl (or acyl) -γ-butyrolactones, 4a-4e and o-phenylenediamine or 2, 3-diaminonaphthalene leads under retrograde aldol condensation involving loss of formaldehyde to formation of 3-substituted-3, 4-dihydro-2 (1H) quinoxalinones or benzo [g] quinoxalinones, 7a-7g , respectively as a new convenient synthesis of this type of heterocyclic systems. The reaction of type 4 compound with 4, 5-diaminopyromidine, 8 , was found to proceed differently. 2-[(4-Amino-5-pyrimidinyl)amine]-4-oxo-3-(hydroxymethyl)-4-phenyl-2-butenoic acid 9 was the only product formed when the reaction between 4a and 8 was run in ethanol. The same reaction in glacial acetic acid proceeds with loss of formaldehyde, to afford 7-phenacylidene-7,8-dihydro-6 (1H)-pteridione 10 . The reaction between type 4 compounds and ethylenediamine or 1, 4-phenylenediamine leads to the formation of the bis-condensation products 13–15 , respectively. 相似文献
3.
Josef Becker Josef Ehrenfreund Oskar Jeger Günther Ohloff Hans Richard Wolf 《Helvetica chimica acta》1974,57(8):2679-2703
UV.-irradiation of iso-methyl-α, (E)-ionone ( 4 ) in neutral solvents yields iso-methyl-α, (Z)-ionone ( 5 ), the bicyclic ether 6 and the epoxide 7 by a sequence of successive photoisomerizations. The steps leading to des-methyl homologues of 6 and 7 do not occur on irradiation of α, (E)-ionone ( 1 ) [10]. The reversible isomerization 4 ? 5 is followed by the irreversible photoprocess 5 → 6 and the final transformation 6 → 7 . Irradiation of iso-methyl-α, (E)-ionone ( 4 ) in acidic or basic solvents leads to a deep change in the type of products and gives the isomeric ketones 9 and 10 in high yields. A tentative mechanism for the photoisomerization steps 5 → 6, 6 → 7 and 5 → 9 + 10 is proposed. 相似文献
4.
Sodium perfluoroalkanesulfinate, RFSO2Na [RF?Cl(CF2)4, 1a; CF3(CF2)5, 1b; Cl(CF3)6, 1c] reacted with bromine in aqueous solution to give the corresponding sulfonyl bromide RFSO2Br (2a-2c) and in acetonitrile or acetic acid, to form perfluoroalkyl bromide RFBr (3a-3c). Heating in acetonitrile at 80°C, 2a-2c were converted smoothly into 3a-3c. However, reaction of sodium α,α-dichloropolyfluoroalkanesulfinate RCCl2SO2Na (R?CF3, Cl(CF2)n, n=2, 4, 6, 5a-5d) with bromine in aqueous solution gave directly the corresponding bromoalkanes 1-bromo-1,1-dichloropolyfluoroalkane RCCl2Br (6a-6d). In aqueous potassium iodide solution, 1a-1c, 5a and 5b also reacted with iodine to form the corresponding iodo-polyfluoroalkane 4a-4c, 7a and 7b directly. 6a and 7a underwent free radical addition to alkene readily in the presence of free radical initiator and reacted with Na2S2O4 in the usual way to form α,α-dichloropolyfluoroethane sulfinate (5a). 5a was stable in strong acid, but reacted with strong base to yield 10. 5a was oxidised by hydrogen peroxide to the sulfonate 11 and reduced by zinc in dilute acid to from the α-chloro sulfinate 12. 相似文献
5.
Cherngy-Chyi Tzeng Yue-Ling Zhao Yeh-Long Chen Shorong-Shii Liou Tai-Chi Wang Ya-Ling Chang Che-Ming Teng 《Helvetica chimica acta》1997,80(8):2337-2344
In a search for inhibitors of platelet aggregation, a number of α-methylidene-γ-butyrolactones 5 and 6 bearing flavone or xanthone moieties, respectively, were synthesized and evaluated for their antiplatelet activity against thrombin(Thr)-, arachidonic-acid(AA)-, collagen(Col)?, and platelet-activating-factor(PAF)-induced aggregation in washed rabbit platelets. These compounds were synthesized from 7-hydroxyflavone ( 1 ) or 3-hydroxyxanthone ( 2 ) via O-alkylation (→ 3 and 4 , resp.) and Reformatsky-type condensation (Scheme). Most of the flavone-containing α-methylidene-γ-butyrolactones 5a – d showed potent antiplatelet effects on AA- and Col-induced aggregation, while xanthone derivatives 6c – e were found to have the same pharmacological profile than aspirin in which only AA-induced aggregation was inhibited (Table 1). However, 6c – e were approximately three to ten times more potent than aspirin (Table 2). For the vasorelaxing effects, 5a was the only compound which exhibited significant inhibitory activity on the high-K+ medium, Ca2+-induced vasoconstriction (Table3). Both 5a and 6a , with an aliphatic Me substituent at C(γ) of the lactone, were active against norepinephrine-induced phasic and tonic constrictions while their γ-aryl-substituted counterparts 5b – f and 6b – f were inactive. 相似文献
6.
Andor Fürst Ludvik Labler Werner Meier Karl-Heinz Pfoertner 《Helvetica chimica acta》1973,56(5):1708-1710
1α-hydroxycholesterol ( 4a ) was synthesized from cholesterol and transformed via its diacetyl derivative 4b into 1α, 3β-diacetoxycholesta-5, 7-diene ( 6b ). Irradiation of the ring-B-diene 6b followed by thermal isomerization and saponification gave 1α-hydroxycholecalciferol ( 7 ). 相似文献
7.
A. Lffler F. Norris W. Taub K. L. Svanholt A. S. Dreiding 《Helvetica chimica acta》1970,53(2):403-417
By heating with iron powder at 120–150° some γ-bromo-α, β-unsaturated carboxylic methyl esters, and, less smothly, the corresponding acids, were lactonized to Δ7alpha;-butenolides with elimination of methyl bromide. The following conversions have thus been made: methyl γ-bromocrotonate ( 1c ) and the corresponding acid ( 1d ) to Δα-butenolide ( 8a ), methyl γ-bromotiglate ( 3c ) and the corresponding acid ( 3d ) to α-methyl-Δα-butenolide ( 8b ), a mixture of methyl trans- and cis-γ-bromosenecioate ( 7c and 7e ) and a mixture of the corresponding acids ( 7d and 7f ) to β-methyl-Δα-butenolide ( 8c ). The procedure did not work with methyl trans-γ-bromo-Δα-pentenoate ( 5c ) nor with its acid ( 5d ). Most of the γ-bromo-α, β-unsaturated carboxylic esters ( 1c, 7c, 7e and 5c ) are available by direct N-bromosuccinimide bromination of the α, β-unsaturated esters 1a, 7a and 5a ; methyl γ-bromotiglate ( 3c ) is obtained from both methyl tiglate ( 3a ) and methyl angelate ( 4a ), but has to be separated from a structural isomer. The γ-bromo-α, β-unsaturated esters are shown by NMR. to have the indicated configurations which are independent of the configuration of the α, β-unsaturated esters used; the bromination always leads to the more stable configuration, usually the one with the bromine-carrying carbon anti to the carboxylic ester group; an exception is methyl γ-bromo-senecioate, for which the two isomers (cis, 7e , and trans, 7d ) have about the same stability. The N-bromosuccinimide bromination of the α,β-unsaturated carboxylic acids 1b , 3b , 4b , 5b and 7b is shown to give results entirely analogous to those with the corresponding esters. In this way γ-bromocrotonic acid ( 1 d ), γ-bromotiglic acid ( 3 d ), trans- and cis-γ-bromosenecioic acid ( 7d and 7f ) as well as trans-γ-bromo-Δα-pentenoic acid ( 5d ) have been prepared. Iron powder seems to catalyze the lactonization by facilitating both the elimination of methyl bromide (or, less smoothly, hydrogen bromide) and the rotation about the double bond. α-Methyl-Δα-butenolide ( 8b ) was converted to 1-benzyl-( 9a ), 1-cyclohexyl-( 9b ), and 1-(4′-picoly1)-3-methyl-Δα-pyrrolin-2-one ( 9 c ) by heating at 180° with benzylamine, cyclohexylamine, and 4-picolylamine. The butenolide 8b showed cytostatic and even cytocidal activity; in preliminary tests, no carcinogenicity was observed. Both 8b and 9c exhibited little toxicity. 相似文献
8.
Elena I. Klimova Tatiana Klimova Marcos Flores Alamo José M. Méndez Stivalet Lena Ruíz Ramírez Leon V. Backinowsky Marcos Martínez García 《Journal of heterocyclic chemistry》2011,48(2):441-448
The reactions of α‐ferrocenylmethylidene‐β‐oxocarboxylates ( 1 , 2 , 3a , and 3b ) with N‐methyl‐ and N‐(2‐hydroxyethyl)hydrazines ( 5a , 5b ) afford ethyl 1‐alkyl‐5‐aryl(methyl)‐3‐ferrocenylpyrazole‐4‐carboxylates ( 6a , 6b , 6c , 6d , 6e ) (~50%) and N‐alkylhydrazine insertion products, viz., ethyl (N′‐acyl‐N′‐alkylhydrazino)‐3‐ferrocenylpropanoates ( 7a , 7b , 7c , 7d , 7e ) (~20%) and 1‐acyl‐2‐(N′‐alkyl‐N′‐ethoxycarbonylhydrazino)‐2‐ferrocenylethanes ( 8a , 8b , 8c , 8d , 8e ) (~10%). The structures of the compounds obtained were established based on the spectroscopic data and X‐ray diffraction analysis (for pyrazoles 6a and 6b ). J. Heterocyclic Chem., (2011). 相似文献
9.
Kazuo Murato Bruno Frei Wolfhard Bernd Schweizer Hans Richard Wolf Oskar Jeger 《Helvetica chimica acta》1980,63(7):1856-1866
On triplet sensitization (E)- 5 gives (Z)- 5 and isomerizes via C(δ), O-bond cleavage to the cyclobutanone 6 and the conjugated γ-ketoester 7 . - On singulet excitation 6 undergoes decarbonylation and yields the bicyclo [4.1.0]heptane 8 . However, on triplet sensitization 6 is converted to the isomeric tricyclononane 9 by a stereospecific oxa-di-π-methane rearrangement. The structure of 9 is determined by X-ray analysis of the p-nitrobenzoate 15: a = 10.573, b = 14.707, c = 13.494 Å, β = 112.40°, P21/n, Z, = 4. 相似文献
10.
Guido Settimj Maria Rosaria Del Giudice Rosella Ferretti Franco Gatta 《Journal of heterocyclic chemistry》1988,25(5):1391-1397
Condensation of diethyl formylamino- or diethyl acetylaminomalonate with 4-, 5- or 6-nitrogramine 1 afforded the diethyl formylamino- or the diethyl acetylamino[(nitroindol)-3-ylmethyl]malonates 2 ; reduction of the nitro group followed by N-formylation or acetylation of the resulting amino compounds 3 , led to the 4-, 5-and 6-acylamino derivatives 4 . Cyclization of 4 in the presence of polyphosphoric esters gave the 3,3-bis(ethoxycarbonyl)-3,4-dihydro-β-carbolines 5 , which underwent lithium chloride/water catalyzed monodeethoxycarbonylation to the corresponding 5-, 6- and 7-acylamino-3-ethoxycarbonyl-β-carbolines 6 , whose acidic hydrolysis led finally to the 5-, 6- and 7-amino-3-ethoxycarbonyl-β-carbolines 9 . The 6-amino compounds 9b-e were obtained also by direct nitration of 3-methoxycarbonyl-β-carboline 7a and of 3-ethoxycarbonyl-β-carboline 7c , followed by the nitro group reduction of the resulting nitro carbolines 8 . Preliminary studies of the binding to rabbit brain benzodiazepine receptor sites indicate compounds 9b and 9c to inhibit the 3H-diazepam binding at 10?8 M concentrations. 相似文献
11.
Antoine Gautier Christian Vial Cdric Morel Marina Lander Ferdinand Nf 《Helvetica chimica acta》1987,70(8):2039-2044
The enantiomeric decahydro-2-naphthalenols (+)- 5 and (?)-5 were prepared by enantioselective hydrolysis of the racemic chloroacetate (±)- 2 catalyzed by porcine pancreatic lipase, and converted to the corresponding acetates (+)- 1 and (?)- 1 and ketones (+)- 6 and (?)- 6 . The absolute configurations of the ketones, alcohols, and acetates were established by chemical correlation with natural manool ((+)- 7 ) by making use of a retro-ene cleavage reaction of the known manool degradation product 8 to (?)- 6 . A distinct odour difference between the two enantiomers of each pair (+)- 1 /(?)- 1 and (+)- 6 /(?)- 6 has been found. 相似文献
12.
Meso- ( 1a ) and racemic dimethyl α,α'-dibromo o-benzenediacetate ( 1b ) when condensed with hydrazine and methylhydrazine furnished respectively 1,3-dicarbomethoxyisoindole ( 5a ) and its N-methyl derivative ( 5b ). Reaction of phenylhydrazine with 1a led to the N-phenylisoindole ( 5c ) and to the N-anilino isoindoline ( 6 ) as the cis isomer; conversely, 1b was transformed into a mixture of the 2-phenyl-1,2,3,4-tetrahydrophthalazine ( 7 ), the trans isomer of ( 6 ), the N-anilinoisoindole ( 5d ) and dimethyl α-(N'-phenylhydrazino)-o-benzenediacetate ( 8 ). Compounds 1a and 1b were also condensed with acetylhydrazine to give a mixture of the N-acetylaminoisoindoline ( 12 ) and of the 2-acetyl-1,2,3,4-tetrahydrophthalazine ( 13 ). 相似文献
13.
Shogo Ihara Takashi Soma Daigo Yano Shunichi Aikawa Yasuhiko Yoshida 《Journal of heterocyclic chemistry》2011,48(3):577-581
The cycloaddition reaction of cyclic imidates, 2‐benzyl‐5,6‐dihydro‐4H‐1,3‐oxazines 1a , 1b , 1c , 1d , 1e , 1f , with dimethyl acetylenedicarboxylate 2 , trimethyl ethylenetricarboxylate 4 , or dimethyl 2‐(methoxymethylene)malonate 6 afforded new fused heterocyclic compounds, such as methyl (6‐oxo‐3,4‐dihydro‐2H‐pyrrolo[2,1‐b]‐1,3‐oxazin‐7‐ylidene)acetates 3a , 3b , 3c , 3d , 3e , 3f (71–79%), dimethyl 2‐(6‐oxo‐3,4,6,7‐tetrahydro‐2H‐pyrrolo[2,1‐b]‐1,3‐oxazin‐7‐yl)malonates 5b , 5c , 5d , 5e , 5f (43–71%), or methyl 6‐oxo‐3,4‐dihydro‐2H,6H‐pyrido[2,1‐b]‐1,3‐oxazine‐7‐carboxylates 7a , 7b , 7c , 7d , 7e , 7f (32–59%), respectively. In these reactions, 1a , 1b , 1c , 1d , 1e , 1f (cyclic imidates, iminoethers) functioned as their N,C‐tautomers (enaminoethers) 2 to α,β‐unsaturated esters 2 , 4, and 6 to give annulation products 3 , 5 , and 7 following to the elimination of methanol, respectively. J. Heterocyclic Chem., (2011). 相似文献
14.
Irradiation in the n→π* absorption band of the α,β-unsaturated γ,δ-epoxyketone 5 in ethanol at ?65° exclusively afforded the rearranged ene-dione 13 , whereas at + 24° under otherwise unchanged reaction conditions or upon triplet sensitization with Michler's ketone and with acetophenone at + 24° essentially identical mixtures of 13 (major product), 14 , and 15 were obtained. Selective π→π* excitation of 5 at ?78° and + 24° led to similar product patterns. The 9β,10β-epimeric epoxyketone 7 selectively isomerized to 14 and 15 at + 24° and n → π* or π → π* excitation. Neither the epoxyketones 5 and 7 nor the photoproducts 13–15 were photochemically interconverted. In separate photolyses each of the latter gave the double bond isomers 16 , 18 , and 19 , respectively. Cleavage of 13 to the dienone aldehyde 17 competed with the double bond shift ( → 16 ) when photolyzed in alcoholic solvents instead of benzene. The selective transformations 5 → 13 (at ?65° and n → π* excitation) and 7 → 14 + 15 are attributed to stereoelectronic factors facilitating the skeletal rearrangements of the diradicals 53 and 55 , the likely primary photoproducts resulting from epoxide cleavage in the triplet-excited compounds 5 and 7 , via the transition states 54 , 56 , and 57 . The loss of selectivity in product formation from 5 at higher temperature and n → π* excitation or triplet sensitization is explicable in terms of radical dissociation into 58 and 59 increasingly participating at the secondary thermal transformations of 53 . The similar effect of π → π* excitation even at ?78° indicates that some of the π,π* singlet energy may become available as thermal activation energy. It is further suggested that the considerably lesser ring strain in 14 and 15 , as compared with 13 , is responsible that selectivity in product formation from 7 is maintained also at +24° and at π → π* excitation. 相似文献
15.
Stereoselective Reductive Dimerisation of α-Cyano-β-(4-pyridyl)acrylic Acid Derivatives Catalytic hydrogenation of the α-substituted β-(4-pyridyl)acrylonitriles 3 and 4 (see Scheme 3) yields via stereoselective reductive dimerization the substituted cyclo-pentene derivatives 7 and 8 (see Scheme 4 and 5) instead of the expected dihydro-products 5 and 6 . The mechanism of this reaction is discussed. The structure and relative configuration of 10 have been established by X-ray single crystal analysis. 相似文献
16.
Pierre Martin Hans Greuter Tammo Winkler Daniel Bellu Grety Rihs 《Helvetica chimica acta》1981,64(8):2571-2586
Rearrangement of α-Halogen- to α′-Halogen-cyclobutanones, Key Step of a Highly Versatile Synthesis of Pyrethroids α-Halogenocyclobutanones, which are readily available by [2 + 2]-cycloaddition of haloketenes to terminal olefins (e. g. 5 → 6 ), undergo an efficient and stereoselective cine-rearrangement to α′-halogenocyclobutanones in the presence of catalysts such as tertiary amines, HX acids or quaternary ammonium salts (e. g. 6 → 7 , Table 1). Preparative as well as mechanistic aspects of the cine-rearrangement are discussed. The 2,4-cis-disubstituted cyclobutanones 7–32 thus formed represent valuable intermediates in a new synthesis of pyrethroids 1 . The X-ray structure of 2-chloro-4-(2,2,2-trichloroethyl)-3,3-dimethylcyclobutanone ( 7 ), the most important precursor of cis- 3 (X = Cl) shows the following features: a puckered cyclobutanone ring (dihedral angle 31°), 2,4-cis-di-pseudoequatorial arrangement of the chloro and trichloroethyl substituents, and an endo-deviation (0.225 Å; 11°) of the carbonyl O-atom from the plane formed by C(1), C(2) and C(4) (Fig. 2). 相似文献
17.
Patrice Renaut Jean Millet Christiane Sepulchre Jocelyne Theveniaux Vronique Barberousse Vincent Jeanneret Pierre Vogel 《Helvetica chimica acta》1998,81(11):2043-2052
Mitsunobu displacement of (−)-(1S,4R,5S,6S)-4,5,6-tris{[(tert-butyl)dimethylsilyl]oxy}cyclohex-2-en-1-ol ((−)- 12 ; a (−)-conduritol-F derivative) with 4-ethyl-7-hydroxy-2H-1-benzopyran-2-one ( 16 ) provided a 5a-carba-β-D -pyranoside (+)- 17 that was converted into (+)-4-ethyl-7-[(1′R,4′R,5′S,6′R)-4′,5′,6′-trihydroxycyclohex-2′-en-1′-yloxy]-2H-1-benzopyran-2-one ((+)- 5 ) and (+)-4-ethyl-7-[(1′R,2′R,3′S,4′R)-2′,3′,4′-trihydroxycyclohexyloxy]-2H-1-benzopyran-2-one ((+)- 6 ). The 5a-carba-β-D -xyloside (+)- 6 was an orally active antithrombotic agent in the rat (venous Wessler's test), but less active than racemic carba-β-xylosides (±)- 5 and (±)- 6 . The 5a-carba-β-L -xyloside (−)- 6 was derived from the enantiomer (+)- 12 and found to be at least 4 times as active as (+)- 6 . (+)-4-Cyanophenyl 5-thio-β-L -xylopyranoside ((+)- 3 ) was synthesized from L -xylose and found to maintain ca. 50% of the antithrombotic activity of its D -enantiomer. Compounds (±)- 5 , (±)- 6 , and (−)- 6 are in vitro substrates for galactosyltransferase 1. 相似文献
18.
Yeh-Long Chen Tai-Chi Wang Cherng-Chyi Tzeng Nein-Chen Chang 《Helvetica chimica acta》1999,82(2):191-197
To determine some of the structural features of geiparvarin that account for its cytostatic activity in vitro, certain geiparvarin analogues modified in the furan-3(2H)-one moiety and the alkenyloxy substituent were synthesized and tested against the growth of 60 human cancer cell lines derived from nine cancer-cell types. These compounds demonstrated a strong growth-inhibitory activity against leukemia cell lines but were relatively inactive against non-small-cell lung cancers and CNS cancers. Comparison of the mean log GI50 values of γ-[(E)-1-methylprop-1-enyl]-α-methylidene-γ-butyrolactones 7 – 9 revealed that 7-[(E)-3-(2,3,4,5-tetrahydro-4-methylidene-5-oxofuran-2-yl)but-2-enyloxy]-2H- 1-benzopyran-2-one ( 8 ; −5.47) was more active than its 6-substituted counterpart 7 (−5.21) and its 3-chloro-4-methyl derivative 9 (−5.31) and had a potency similar to that of geiparvarin (log GI50=−5.41). These results indicated that the furan-3(2H)-one moiety of geiparvarin could be replaced by an α-methylidene-γ-butyrolactone unit without losing the anticancer potency, and that the best substitution site at the coumarin moiety was C(7). The alkenyloxy substituent of 8 was also replaced by a methoxy substituent. Among these α-methylidene-γ-butyrolactones, 7-[(2,3,4,5-tetrahydro-4-methylidene-5-oxo-2-phenylfuran-2-yl)methoxy]-2H-1-benzopyran-2-one ( 11 ) was the most potent with a mean log GI50 value of −5.83 and a range value of 132 (102.12). 相似文献
19.
Tordanone, a Twice Bent Steroid Structure with Ring A/B β-cis(5β)- and Ring B/C α-cis(8α)-Fused The 3β, 14α, 25-trihydroxy-5β, 8α-cholestan-6-one ( = tordanone; 4 ) has been prepared by stereospecific hydrogenation of 3β, 14α, 25-trihydroxy-5β-cholesta-7,22ξ-dien-6-one ( 5 ). This is the first stereospecific synthesis of a B/C cis-fused steroid belonging to the 5β, 8α -cholestane group with a H-atom at positions 5β (A/B cis-fused) and 8α. The resulting twice bent structure shows a particularly strong steric hindrance of the β-face where CH3(18) at the C/D ring junction and Hβ? C(7) of the B ring are very close to each other. Structural features and mechanistic aspects of the hydrogenation are discussed. 相似文献
20.
Gyrgy Frter 《Helvetica chimica acta》1977,60(2):515-517
Synthesis of (±)-α-Chamigrene Cis- and trans-β-ionol (cis and trans- 1 ) underwent acid catalysed dehydration to a mixture of the tetraenes 2–5 in 70–80% yield (Table 1). Irradiation of this mixtures made the 6-(Z), 8-(Z)-isomer 5 accessible (columns 3 and 4 in Table 1). Pyrolysis of the different mixtures at 170° showed, that both isomers, 3 and 5 respectively undergo electrocyclization to dehydrochamigrene ( 6 ). The latter was reduced to α-chamigrene ( 7 ) by hydrogen on Lindlar catalyst. 相似文献